Geir Grung (13 December 1926 – 16 March 1989) was a Norwegian architect.
He was born in Bergen as a son of architect Leif Kuhnle Grung, and took his education at the Norwegian National Academy of Craft and Art Industry in 1949. He studied together with Sverre Fehn, and cooperated with him on several occasions. From 1954 he ran an architect's office together with Georg Greve. When Greve retired in 1970, Grung continued on his own. Grung was a modernist, and was involved in the Congrès International d'Architecture Moderne.
Grung was married twice.